The issue was that the used operator just took the active node into account. However, clicking in empty space does not make the active node inactive. Therefore, sometimes clicking on empty space would sometimes remove enter the last selected group node. Furthermore, double clicking on other nodes may also trigger exiting the current group. This is fixed by introducing a new operator that explicitly checks what node is hovered. Pull Request: https://projects.blender.org/blender/blender/pulls/147053